Tooth decay and dental disease can be caused by bacterial action resulting from the formation of plaque about the teeth and/or the entrapment of food particles in interstices between the teeth. Removal of plaque and entrapped food particles reduces the incidence of caries, gingivitis, and mouth odors as well as generally improving oral hygiene. Conventional brushing has been found to be inadequate for removing all entrapped food particles and plaque. To supplement brushing, dental flosses and tapes have been recommended.
Dental flosses including a thickened "brush" portion have been developed. These flosses may also include a thin "floss" portion and a threader. The brush portion, when drawn between tooth surfaces, provides good cleaning action which removes materials left by a standard thin floss used alone.
To form a brush floss, it is necessary to provide bulked filaments in a strand of floss, i.e., filaments which are separated and have a somewhat sinuous, random orientation.
Dental flosses, both in brush and thin floss form, often include additives such as flavors or colors. These flavors have been conventionally applied by coating the additive onto the surface of the floss.
Conventionally, polymers coating a filament are applied as solutions dissolved in a solvent. The production of polymer-covered filaments entails delay in the time required for the solvent to evaporate, generation of polluting solvent vapors, and the danger of residual unevaporated solvents. There is a need for improved filament coatings and for an improved method of producing a polymer-coated filament.